Making an analysis for vibration modal and frequency response of the lathe spindle,respectively by using finite element method based on ANSYS and experiment of CA6140 type lathe in machining,and the calculation result...Making an analysis for vibration modal and frequency response of the lathe spindle,respectively by using finite element method based on ANSYS and experiment of CA6140 type lathe in machining,and the calculation results are compared and analyzed,which verified the accuracy of ANSYS method. Numerical simulation and experimental results show that: Spindle in the first order and fifth order are prone to resonance,but did not reach resonance,the low order natural frequency have more effect than the high order natural frequency of the spindle vibration; by the experiments can conclude that the maximum vibration of the main shaft in the working state is mainly concentrated in the vicinity of its two ends,therefore,the improved bearing is an important way to reduce the vibration of the main shaft and ensure the machining accuracy,and the research results can provide a theoretical reference for the structural optimization design of the lathe.展开更多
As to motorized spindle system, this paper builds a simplified 3D model of spindle and bearing, performs structure modal analysis, reveals its dynamic characteristics under the free model; furthermore, modifies bearin...As to motorized spindle system, this paper builds a simplified 3D model of spindle and bearing, performs structure modal analysis, reveals its dynamic characteristics under the free model; furthermore, modifies bearing radial stiffness and number of model and studies the change of modal parameters. On this basis, through the harmonic response analysis of the finite element model, dy- namic response characteristic caused by imbalance of monitored spindle system and law of vibration response to different amount of unbalance is analyzed.展开更多
A rotating packed bed is a typical chemical process enhancement equipment that can strengthen micromixing and mass transfer.During the operation of the rotating packed bed,the nonreactants and products irregularly adh...A rotating packed bed is a typical chemical process enhancement equipment that can strengthen micromixing and mass transfer.During the operation of the rotating packed bed,the nonreactants and products irregularly adhere to the wire mesh packing in the rotor,thus resulting in an imbalance in the vibration of the rotor,which may cause serious damage to the bearing and material leakage.This study proposes a model prediction for estimating the bearing residual life of a rotating packed bed based on rotor imbalance response analysis.This method is used to determine the influence of the mass on the imbalance in the vibration of the rotor on bearing damage.The major influence on rotor vibration was found to be exerted by the imbalanced mass and its distribution radius,as revealed by the results of orthogonal experiments.Through implementing finite element analysis,the imbalance response curve for the rotating packed bed rotor was obtained,and a correlation among rotor imbalance mass,distribution radius of imbalance mass,and bearing residue life was established via data fitting.The predicted value of the bearing life can be used as the reference basis for an early safety warning of a rotating packed bed to effectively avoid accidents.展开更多
Double-shaft-driven needle punching machine is a specialized equipment designed for processing C/C crucible preforms.Its main needle punching module is operated by two sets of reciprocating crank-slider mechanisms.The...Double-shaft-driven needle punching machine is a specialized equipment designed for processing C/C crucible preforms.Its main needle punching module is operated by two sets of reciprocating crank-slider mechanisms.The intense vibration during needle punching not only generates huge noise,but also substantially reduces the quality of the preform.It is imperative to perform a dynamic analysis and optimization of the entire needle punching machine.In this paper,the three-dimensional(3D)model of the entire double-shaft-driven needle punching machine for C/C crucible preforms is established.Based on the modal analysis theory,the modal characteristics of the needle punching machine under various operating conditions are analyzed and its natural frequencies and vibration modes are determined.The harmonic response analysis is then employed to obtain the amplitude of the needle plate at different frequencies,and the structural weak points of the needle punching machine are identified and improved.The feasibility of the optimized scheme is subsequently reevaluated and verified.The results indicate that the first six natural frequencies of the machine increase,and the maximum amplitude of the needle plate decreases by 70.3%.The enhanced dynamic characteristics of the machine significantly improve its performance,enabling more efficient needle punching of C/C crucible preforms.展开更多
A new type of vibration structure (i.e. supporting system, called swing frame cus- tomarily) of vertical dynamic balancing machine has been designed, which is based on an analysis for the swing frame of a traditiona...A new type of vibration structure (i.e. supporting system, called swing frame cus- tomarily) of vertical dynamic balancing machine has been designed, which is based on an analysis for the swing frame of a traditional double-plane vertical dynamic balancing machine. The static unbalance and couple unbalance can be e?ectively separated by using the new dynamic balancing machine with the new swing frame. By building the dynamics model, the advantages of the new structure are discussed in detail. The modal and harmonic response are analyzed by using the ANSYS7.0. By comparing the ?nite element modal analysis with the experimental modal analy- sis, the natural frequencies and vibration modes are found. There are many spring boards in the new swing frame. Their sti?nesses are di?erent and assorted with each other. Furthermore, there are three sensors on the measuring points. Therefore, the new dynamic balancing machine can measure static unbalance and coupling unbalance directly, and the interaction between them is faint. The result shows that the new vertical dynamic balancing machine is suitable for inertial measurement of ?ying objects, and can overcome the shortcomings of traditional double-plane vertical dynamic balancing machines, which the e?ect of plane-separation is inferior. The vertical dynamic balancing machine with the new vibration structure can ?nd wide application in the future. The modelling and analysis of the new vibration structure will provide theoretical basis and practical experience for designing new-type vertical dynamic balancing machines.展开更多
The ultrasonic bone scalpel was often used in all kinds of clinical orthopedic surgery as a new type of medical instrument.Based on the working theory of the ultrasonic bone scalpel and combined with the design method...The ultrasonic bone scalpel was often used in all kinds of clinical orthopedic surgery as a new type of medical instrument.Based on the working theory of the ultrasonic bone scalpel and combined with the design method of a quarter wavelength transducer and horn,this study proposed an optimization design method for the ultrasonic bone scalpel with a composite horn structure.The structure of the ultrasonic bone scalpel was simplified,and its length was shortened.Finite element analysis,modal analysis,and harmonic response analysis were used to optimize the design of the ultrasonic bone scalpel.The performance of the ultrasonic bone scalpel was explored through impedance analysis,amplitude measurement,temperature measurement,and cutting tests,and the feasibility of the design was verified through torque analysis.The results showed that when the torque force was 4.0 N,the resonance frequency of the ultrasonic bone scalpel was 30,540 Hz,and the maximum amplitude of the ultrasonic bone scalpel could reach 62μm.After spray cooling,the maximum surface temperature of the rear end cover was reduced from 51.8 to 36.3℃,the maximum surface temperature of the composite horn was reduced from 71 to 45.3℃,and the maximum surface temperature of the cutter head was reduced from 101 to 46.1℃,demonstrating a good cooling effect.Under 89 Voltage,the optimal cutting force for cutting chicken leg bones was 0.1 N,the optimal cutting force for cutting pork ribs was 0.3 N,and the cutting process showed tissue selectivity.展开更多
基金financially supported by Independent Innovation Research Fund of Wuhan University of Technology(No.2014-ND-B1-09)
文摘Making an analysis for vibration modal and frequency response of the lathe spindle,respectively by using finite element method based on ANSYS and experiment of CA6140 type lathe in machining,and the calculation results are compared and analyzed,which verified the accuracy of ANSYS method. Numerical simulation and experimental results show that: Spindle in the first order and fifth order are prone to resonance,but did not reach resonance,the low order natural frequency have more effect than the high order natural frequency of the spindle vibration; by the experiments can conclude that the maximum vibration of the main shaft in the working state is mainly concentrated in the vicinity of its two ends,therefore,the improved bearing is an important way to reduce the vibration of the main shaft and ensure the machining accuracy,and the research results can provide a theoretical reference for the structural optimization design of the lathe.
基金Special Topic of the Ministry of Education about Humanities and Social Sciences(12JDGC007)National Science and Technology Support Project(2011BAF09B01)Key State Science and Technology Projects(2009ZX04010-021)
文摘As to motorized spindle system, this paper builds a simplified 3D model of spindle and bearing, performs structure modal analysis, reveals its dynamic characteristics under the free model; furthermore, modifies bearing radial stiffness and number of model and studies the change of modal parameters. On this basis, through the harmonic response analysis of the finite element model, dy- namic response characteristic caused by imbalance of monitored spindle system and law of vibration response to different amount of unbalance is analyzed.
基金the High-Performance Computing Platform of Beijing University of Chemical Technology(BUCT)for supporting this papersupported by the Fundamental Research Funds for the Central Universities(JD2319)+2 种基金the CNOOC Technical Cooperation Project(ZX2022ZCTYF7612)the National Natural Science Foundation of China(51775029,52004014)the Chinese Universities Scientific Fund(XK2020-04)。
文摘A rotating packed bed is a typical chemical process enhancement equipment that can strengthen micromixing and mass transfer.During the operation of the rotating packed bed,the nonreactants and products irregularly adhere to the wire mesh packing in the rotor,thus resulting in an imbalance in the vibration of the rotor,which may cause serious damage to the bearing and material leakage.This study proposes a model prediction for estimating the bearing residual life of a rotating packed bed based on rotor imbalance response analysis.This method is used to determine the influence of the mass on the imbalance in the vibration of the rotor on bearing damage.The major influence on rotor vibration was found to be exerted by the imbalanced mass and its distribution radius,as revealed by the results of orthogonal experiments.Through implementing finite element analysis,the imbalance response curve for the rotating packed bed rotor was obtained,and a correlation among rotor imbalance mass,distribution radius of imbalance mass,and bearing residue life was established via data fitting.The predicted value of the bearing life can be used as the reference basis for an early safety warning of a rotating packed bed to effectively avoid accidents.
基金Open Project of Shanghai Key Laboratory of Lightweight Composite,China(No.2232021A4-04)。
文摘Double-shaft-driven needle punching machine is a specialized equipment designed for processing C/C crucible preforms.Its main needle punching module is operated by two sets of reciprocating crank-slider mechanisms.The intense vibration during needle punching not only generates huge noise,but also substantially reduces the quality of the preform.It is imperative to perform a dynamic analysis and optimization of the entire needle punching machine.In this paper,the three-dimensional(3D)model of the entire double-shaft-driven needle punching machine for C/C crucible preforms is established.Based on the modal analysis theory,the modal characteristics of the needle punching machine under various operating conditions are analyzed and its natural frequencies and vibration modes are determined.The harmonic response analysis is then employed to obtain the amplitude of the needle plate at different frequencies,and the structural weak points of the needle punching machine are identified and improved.The feasibility of the optimized scheme is subsequently reevaluated and verified.The results indicate that the first six natural frequencies of the machine increase,and the maximum amplitude of the needle plate decreases by 70.3%.The enhanced dynamic characteristics of the machine significantly improve its performance,enabling more efficient needle punching of C/C crucible preforms.
基金Project supported by the National Natural Science Foundation of China (No.10176011).
文摘A new type of vibration structure (i.e. supporting system, called swing frame cus- tomarily) of vertical dynamic balancing machine has been designed, which is based on an analysis for the swing frame of a traditional double-plane vertical dynamic balancing machine. The static unbalance and couple unbalance can be e?ectively separated by using the new dynamic balancing machine with the new swing frame. By building the dynamics model, the advantages of the new structure are discussed in detail. The modal and harmonic response are analyzed by using the ANSYS7.0. By comparing the ?nite element modal analysis with the experimental modal analy- sis, the natural frequencies and vibration modes are found. There are many spring boards in the new swing frame. Their sti?nesses are di?erent and assorted with each other. Furthermore, there are three sensors on the measuring points. Therefore, the new dynamic balancing machine can measure static unbalance and coupling unbalance directly, and the interaction between them is faint. The result shows that the new vertical dynamic balancing machine is suitable for inertial measurement of ?ying objects, and can overcome the shortcomings of traditional double-plane vertical dynamic balancing machines, which the e?ect of plane-separation is inferior. The vertical dynamic balancing machine with the new vibration structure can ?nd wide application in the future. The modelling and analysis of the new vibration structure will provide theoretical basis and practical experience for designing new-type vertical dynamic balancing machines.
基金financially supported by the National Natural Science Foundation of China(No.52275420)the Natural Science Foundation of Hunan Province of China(No.2022JJ30136)the Natural Science Foundation of Fujian Province of China(No.2021J05108).
文摘The ultrasonic bone scalpel was often used in all kinds of clinical orthopedic surgery as a new type of medical instrument.Based on the working theory of the ultrasonic bone scalpel and combined with the design method of a quarter wavelength transducer and horn,this study proposed an optimization design method for the ultrasonic bone scalpel with a composite horn structure.The structure of the ultrasonic bone scalpel was simplified,and its length was shortened.Finite element analysis,modal analysis,and harmonic response analysis were used to optimize the design of the ultrasonic bone scalpel.The performance of the ultrasonic bone scalpel was explored through impedance analysis,amplitude measurement,temperature measurement,and cutting tests,and the feasibility of the design was verified through torque analysis.The results showed that when the torque force was 4.0 N,the resonance frequency of the ultrasonic bone scalpel was 30,540 Hz,and the maximum amplitude of the ultrasonic bone scalpel could reach 62μm.After spray cooling,the maximum surface temperature of the rear end cover was reduced from 51.8 to 36.3℃,the maximum surface temperature of the composite horn was reduced from 71 to 45.3℃,and the maximum surface temperature of the cutter head was reduced from 101 to 46.1℃,demonstrating a good cooling effect.Under 89 Voltage,the optimal cutting force for cutting chicken leg bones was 0.1 N,the optimal cutting force for cutting pork ribs was 0.3 N,and the cutting process showed tissue selectivity.
